Bottom sieve for wood pulp digesters



Nov. 2 1931.

E. MORTERUD BOTTOM SIEVE FOR WOOD PULP DIGES TERS Filed Dec. 26, 1980 z vravrfa I -fzarlerud Patented Nov. 24, 1931 UNITED STATES EINAB IOBTEBUD, F TORDEBOD, NEAR I088, NORWAY BQTTOK'BIIBVE FOB WOOD PULP DIGIBTERS E Application filed December 28, 1880, Serial No. 50!,904Qaad in Norway August 19, 1980.

The resent invention relates to the type of wood pulp 'digesters, in which the circulation conduit for the digesting liquor is connected with an annular sieve locatednear the outlet opening of the digester, and the object of the invention is to provide a sieve arrangement, by means of which it is made 7 possible for the sieve to expand and contract freely under the influence of temperature 10 variations, whereas on the other hand the arran ement of the sieve is such that it is not Iihely to cause congestion of the pulp near the outlet or prevent the eas emptying of the digester. This is obtaine in accordance with the present invention by that the annular sieve is only secured to the digester proper at one point of its circumference, whereas itis supported at other points of its circumference in such a manner that a free movement of the sieve may take place with re ard to the digester.

Two onus of the invention are illustrated on the drawings. a v 7 Figs. 1 and 2 are axial sectional view and plan of one form of the invention, and Figs. '3 and 4 are corresponding views of another form of the invention.

form) and is located below a stationary abutment -8 formed integral with the .interior lining of the digesten and serving to conduct the pulp over and past the sieve during the emptyin of the digester. According to this form 0 the invention the sieve is also firmly secured to the digester shell at a point adjacent the place at which the circulation conduit '2, is connected (bolt 4), whereas on the rest of its circumference it is laced C3 loosely on brackets or shelves as in icated at 9, permitting the sieve to expand and contract freely.

Claim:

In a wood pulp digester a circulation conduit for the di esting liquor, a sieve of substantially annu ar shape connected with said circulation conduit and located in the lower part of the digester near the outlet opening thereof, and supporting means for said sieye 'zc- According to the forms illustrated on Fig.

1, 1 is the bottom sieve, which may be in the form of a closed annular or polygonal body and which is connected at one point of its circumference with the circulation conduit 2 leading to the circulation pump. At or adj a-' cent the connecting point with the conduit or tube 2 the annular sieve 1 is secured to the digester 3 by means of a stay 4, which is firmly secured to the shell of the digester,

and at a number of other points 'of its circumference' the annular sieve is supported b means of gins or rods 5, both ends of whic rest in sp erical bearings 6, 7 so as to permit the pins or rods to swing freely in all directions.

Instead of being supported by pins or rods I as illustrated the sieve may also be supported by means of wires or chains 10 as indicated on the drawings.

According to the form of the invention illustrated on Figs. 3 and 4 sieve 1 is in the form of an open ring or polygon (horse shoe 

